Balloon catheters, with or without stents, are used to treat strictures, stenoses, or narrowings in various parts of the human body. Devices of numerous designs have been utilized for angioplasty, stents and grafts or combination stent/grafts. Varied catheter designs have been developed for the dilatation of stenoses and to deliver prostheses to treatment sites within the body lumen.
Illustrative procedures involving balloon catheters include percutaneous transluminal angioplasy (PTA) and percutaneous transluminal coronary angioplasty (PTCA), which may be used to reduce arterial build-up such as caused by the accumulation of atherosclerotic plaque. These procedures involve passing a balloon catheter over a guidewire to a stenosis with the aid of a guide catheter. The guidewire extends from a remote incision to the site of the stenosis, and typically across the lesion. The balloon catheter is passed over the guidewire, and ultimately positioned across the lesion.
Once the balloon catheter is positioned appropriately across the lesion, (e.g., under fluoroscopic guidance), the balloon is inflated, which breaks the plaque of the stenosis and causes the arterial cross section to increase. Then the balloon is deflated and withdrawn over the guidewire into the guide catheter, and from the body of the patient.
In many cases, a stent or other prosthesis must be implanted to provide support for the artery. When such a device is to be implanted, a balloon catheter which carries a stent on its balloon is deployed at the site of the stenosis. The balloon and accompanying prosthesis are positioned at the location of the stenosis, and the balloon is inflated to circumferentially expand and thereby implant the prosthesis. Thereafter, the balloon is deflated and the catheter and the guidewire are withdrawn from the patient.
Administering PTCA and/or implanting a stent at a bifurcation in a body lumen poses further challenges for the effective treatment of stenoses in the lumen. For example, dilating a main vessel at a bifurcation may cause narrowing of the adjacent branch vessel. In response to such a challenge, attempts to simultaneously dilate both branches of the bifurcated vessel have been pursued. These attempts include deploying more than one balloon, more than one prosthesis, a bifurcated prosthesis, or some combination of the foregoing. However, simultaneously deploying multiple and/or bifurcated balloons with or without endoluminal prostheses, hereinafter individually and collectively referred to as a bifurcated assembly, requires accurate placement of the assembly. Deploying multiple stents requires positioning a main body within the main vessel adjacent the bifurcation, and then attempting to position another stent separately into the branch vessel of the body lumen. Alternatives to that include deploying a dedicated bifurcated stent including a tubular body or trunk and two tubular legs extending from the trunk. Examples of bifurcated stents are shown in U.S. Pat. No. 5,723,004 to Dereume et al., U.S. Pat. No. 4,994,071 to MacGregor, and U.S. Pat. No. 5,755,734 to Richter et al.
Additional bifurcation stent delivery systems that provide improved reliable treatment at bifurcations are disclosed, for example, in U.S. Pat. No. 6,325,826 to Vardi et al. and U.S. Pat. No. 6,210,429 to Vardi et al. The contents of these aforementioned patents are incorporated herein by reference.
A need still exists for further improved devices and techniques for treating a bifurcated body lumen. For example, a need further exists for additional stent delivery systems that can be used with stents having a branch access side hole and/or an extendible branch portion.